Wanted 6" 8620, round stock.

Plum Creek

Plum Creek

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H-M Supporter Gold Member
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I realize this is a long shot, but I need 12" of 6" 8620 round stock for excavator bucket pin bosses. Basically I need 4, 3" thick rounds of 6".
Thanks
Howard
 
Is there a reason for selecting 8620 over 4140?
 
Probably welded on and the welder doesn't like 4140. I just went through that argument with the excavator parts I built. He asked for A-36 plate burnouts. I wanted P110 heavy wall tubing and 4140 plate for what I built, all Q&T 34-36 Rc. 8620 is a good carburizing alloy, but according to the chart I link to here there isn't anything I see that makes much difference.

http://www.makeitfrom.com/compare/N...ISI-8620-SNCM220-1.6523-G86200-Ni-Cr-Mo-Steel
 
The Mesquite grubber I'm building, is suffering from what Ulma Doctor refers to as "mission creep". Commercially available grubbers for a 25 ton cost 6K. A little to pricey for my initial goal of clearing my 200 acres. I figured I would use 1" A36 sheet and used shaft material from the scrappers and just scrap it when I was through. Neighbors now want to get their Mesquite removed and looks like some assistance funding might become available, so now it needs to last a bit longer.
Due to the unavailability of anything except a36, I have been buying my stock from a local drilling rig mfg. They recommended 8620 due to weld crack-out problems they have had in the past. P110 was another option they mentioned.
My original plan was to use ht4140 for both the pins and the pin bosses. I thought I would preheat to 450, burn in with 6010 followed by 7018, and cover. Now I am exploring other options like the 8620.
Are there other options besides welding?
 
Offhand I'd say no to that. But if you weld, bevel severely. The guys I was working with said often they bevel 1-1/2" plates down to 1/16" of the edge left. I find that pretty extreme, but they do about 18 passes. I am just now getting to know these guys, but from the work I see that they have done, it's done right and will stay together.

I have a suggestion for the pin though. Go to a hydraulic shop and ask for some used ram material. You'll probably find something with enough good surface to make the pins. It will be SAE and Metric, so chances are good that sizing won't be an issue. The part I just finished was made from a couple of feet of 55mm ram. Of course to cut it you have to grind through the chrome, and on the ram I had it was nearly 1/8" thick. I cross drilled each end for a bolt. I found that a carbide ball nose end mill was able to get through the chrome with little difficulty. Oh and the price was fair. I paid 10 bucks for the 2 feet of material at the hyd shop. Can't complain about a nice hard chromed and polished pin. Kept lubed, it should last a long time.
 
Thanks Tony, I spent a few weeks looking for scrap 80mm hydraulic rams. The hydraulic shops here send most of the larger stuff to the Drilling rig company I mentioned earlier. They operate a hydraulic shop separate from the Rig and Fab side. All the useable scrapped rams go to the machine side for pins etc.
I bought two 21"X 3,25" HT 4140 drops from them, and am turning them down to 80mm. They are my first longer cuts on the lathe and it has taken a bit of fussing and tweaking to get it to turn without taper, but I'm getting there. This is the first pin IMG_3047.jpg
 
Looks like you are getting a nice finish, so that's in your favor. It won't last as long as a chromed pin, but should be plenty strong if it's Q&T material. By the looks of the cut, it is. Pity around Austin there wasn't some scrap ram material.
 
Yes It is a pity. I gave some thought about driving to Houston or up to your neck of the woods. The last time I was up there I stopped in at Longview scrap and there were piles of cylinder rams as well as lengths of discarded stock. Some of it was still in the shipping wrap. Unfortunately I didn't have calipers or time. They were closed for the holidays by the time I got back.. I did snag a 2" plate grabber with good teeth for less than $15.00. It works great.
That pin was hand polished so the appearance may be somewhat misleading.
This is the second pin.
IMG_3115.JPG
 
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